Pulsed radar systems are different from continuous wave (CW) radars. CW radar systems typically include a transmitter that transmits a continuous flow of radio energy to the target, which re-radiates or scatters this energy and returns a small amount to a receiving antenna. A pulsed radar system, however, transmits a repetitive pattern of short pulses. Typically, a pulsed radar system includes a transmitter, for example, a master-oscillator power amplifier (MOPA) transmitter, and a chain of amplifiers that convert and increase the power level from a supplied electrical power to a transmitted signal power, each controlled by a modulator forming the radar pulse. It is possible in more simple radar systems to use a single high power oscillator with no further amplification. In some high performance radars, transmit-receive (T/R) modules include a final amplifier stage. In most designs, a duplexer is operative with the antenna and permits use of the antenna in both the transmit and receive direction. In some pulsed radar systems, a directional or mechanical antenna beam is rotated around the region to be searched. Usually, several pulses are generated per beam position as the mechanical antenna scans. A phased array radar system, on the other hand, may have various “dwells” and use only one transmission per beam position.
In these pulsed radar systems, several pulses can build-up an echo, which is received for non-coherent or video integration. Sensitivity can be improved by using low noise RF preamplifiers and mixing the signal with a local oscillator (LO) signal to produce an IF signal. After extensive digital signal processing within the IF circuitry, a detector can output a video signal on a cathode-ray tube (CRT) or other display.
Although some pulsed radar systems are now manufactured from standard components, and the overall prices for these systems have been dramatically reduced, prior art millimeter wave (MMW) pulsed radar systems, however, have been difficult to design and manufacture at low costs. This difficulty arises because of the difficulty in establishing and/or controlling transmit and receive intermediate frequency (IF) frequencies using synthesizers. Other technical drawbacks encountered with prior art MMW pulsed radio systems include the use of a poor synthesizer design and an inadequate pulse compression. Also, some MMW pulsed radar systems had a poor signal conversion from the MMW signal range to baseband. Other units had poor packaging and radar power efficiency.